Control of central HVAC systems has long been a topic of innovation. Early HVAC systems had only the most rudimentary control: a manual on/off switch. Later systems were fitted with a bimetal thermostat, which afforded them automatic, temperature-dependent control.
Today's thermostats do much more than simply instruct the HVAC system to turn on or off. They allow a user to set the mode of the HVAC system (e.g., heating, cooling or ventilation). They can provide zones of separate thermostatic control. More sophisticated electronic thermostats typically provide setback, which allows setpoint temperatures to vary depending upon time of day or day of week. Some electronic thermostats can give temperature histories, monitor energy usage and even present a graphical image of the surrounding premises to allow individual room control.
A bundle of wires conventionally couples thermostats to the HVAC systems they control. The wires have to be designed and built in to new construction or retrofitted (sometimes with great difficulty) into existing construction, which somewhat limits where thermostats can be placed. Relocating thermostats involves rerouting their associated wires or routing new ones. Thus it is rare that thermostats, once placed, are ever moved.
In an effort to allow a user to place a thermostat where he wants it, the prior art has introduced wireless thermostats that communicate by infrared light. These thermostats are afforded only rudimentary functionality, since they rely solely on batteries for their power. Unfortunately, despite their effort to keep power requirements at a minimum, their batteries require frequent replacement. These thermostats were also constrained by line-of-sight by virtue of their dependence upon light as their carrier.
The prior art has also introduced thermostats that offer sophisticated control features and communicate wirelessly by radio frequency signals. However, these thermostats require external power sources and interconnecting wires to provide sufficient power to the thermostats to support their sophistication. To call these thermostats “wireless” would be a misnomer.
As powerful as these thermostats were, a need continues to exist for evermore control features and flexibility. What is needed in the art is a more powerful and flexible wireless remote control for an HVAC system. What is further needed in the art is a wireless remote control that requires less maintenance (i.e., battery replacement).